Shutter for cameras.



J. BRANDSTETTER.

SHUTTER FOR CAMERAS.

APPLICATION FILED NOV. 2 0, 1911.

1,275,836. Patented Aug. 13, 19i8.

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UNITED STATES PATENT omuon.

JOSEF BRANDSTETTER, OF ROCHESTER, MINNESOT I R To CONLEY RA- COMPANY, OF'BOCHESTEB, MINNESOTA, A GOBIOLRATION OF MINNESOTA.

SHUTTER FOR CAMERAS.

Specification of Letters Patent. Patented Aug. 13, 1918.

Application filed November 20, 1917. Serial No. 202,899.

To all whom it may concern:

Be it known that I, J osnr BRANDSTETTER, a citizen of the United States residing at Rochester, in the county of 'lmsted and State of Minnesota, have invented certain new and useful Improvements in Shutters for Cameras, of which the following is a specification, reference being had therein to the accompanying drawing.

My invention relates to photographic cameras and has for its object the production of improved shutter operating means.

My present invention relates to the type of shutter described and claimed in Letters Patent Nos. 732,175, granted June 30, 1903, and 739,834, granted September 29, 1903, to F. V. and K. E. Conley. In said patented type, a pair of shutter leaves are carried on rotating shafts and fold together so as to overlap when the shafts are turned in-one direction, while they open wide to expose the lens orifice when the shafts are turned in the opposite direction. To accomplish this turning, the shafts have terminal cranks, those on one end being connected so that the shafts will turn simultaneously but in opposite directions, while a single shaft on the other end is connected with an operating bulb and also with a retracting spring, to turn the shutters into closed position. Other features in the patents need not be adverted to herein as the present invention has to do principally with the shaft operating mechanism, and an improved plunger or piston arrangement'for operating the same.

It will be observed that in the former patcuts the retracting ring in each case is attached to the operating crank, and that the whole strain of maintaining the shutter. open is sustained by the bulb mechanism, so that in case of a slow leak or other defect therein, it would be diflicult to maintain the shutters open with certainty and precision, and at the same time have a spring action sufiicient to insure prompt and reliable closing. The patented apparatus, nevertheless, has proved very efficient in practice, and the present invention perfects the same by removing the possibility noted, and rendering the action of the bulb mechanism, and the shutters noiseless, certain, and precise under'all conditions. I

. Very briefly stated, the improvement consists in the provision of an operating (plunger connected to a crank on one shaft, an a long helical retracting spring connected to a crank on the other shaft, the two shafts being connected by means of a connecting rod opened, thus taking all strain off the operating bulb or plunger and preventing any premature operation of the shutter in case of an accidental leak as well as rendering unnecessary an absolutely air-tight fit of the plunger or piston.

y invention is illustrated in the accompanying drawings in which- Figure 1 is a top plan view of my im proved shutter, and

Fig. 2 is a rear elevation of the same.

In the drawings, 1 indicates inside front wall of a camera casing having an exposure opening 2, to be uncovered and covered by the shutter in operation. The shutter proper consists of two leaves 3 and 4, secured respectively to. the shafts 5 and 6, passing through and journaled in top and bottom plates 7 and 8, which serve also as light guards to prevent leakage of light past the edges of the shutters when they are closed. When fully opened, the leaves 3 and 4: are received within cushioning wings 9 and 10 respectively, having extensions supplement; ing the plates 7 and 8, so as to form a complete box around the opening 2. The wall 1 ofthe camera is usually made of wood and inside the box formed of the plates 78 and the wing extension, an extra. thickness of wood is provided covered on its face with felt designated by the numeral 11. When zlosed, the leaves rest against this felt surace.

The two shafts 5 and 6 are provided respectively with cranks 12 and 13, linked together by a connecting rod 14: the cranks being oppositely set, that is to say, one being down while the other is up and the link diagonal, so, that the cranks will turn the shafts in opposite directions when moving together. The shaft 6 has an operating crank 15 connected by means of a straight connecting rod 16 to the plunger or piston 17 of a pneumatic cylinder 18, supplied with air through a nipple l9, and a rubber tube 20 terminating in a bulb 21 having an opening 7 andthe distance of its: anchorage point 25 renders it possible to set the crank 23 so that a straight line connecting it with the-polnt 25 in its two extreme positions would fall on.oppositesides ofgthe crank shaft axis 5;

orin other words so that the spring 24 will snap past center as the shaft 5"oscillates and theshutters 3 and 4 open and close. This is "clearly illustrated in Fig. 1 which shows the shutters open and the spring one side ofthe-crank 23. 1 v

I The pneumatic cylinder 18 is constructed in the-form of an open ended dashpot with the-nipple: 19 on the closed end. The piston 17'is' formed as shown in cup shape with extendeds'ide walls smoothly fitted to the internal walls of the cylinder, which maybe by grinding or otherwise.v r In'operation, the thumb of the operator is placed over the opening 22 in the bulb 20 and the bulb compressed, whereupon air will be-forced in the cylinder 18 behind the piston, forcing the latter 'tothe" right the drawing, thereby turning the crank-'15 and through the connected cranks 13 and 12 and the connecting rod 14, turning'the shaft 5 in the reverse direction, opening the shutters to the extreme position shown in the drawings. The spring 24 having passedcenter tends to maintain the shutter leaves inf-open position, by, keeping a strain on the crank 23, hence the thumb may be removed from the bulb and the operator may have the free use of both hands while the shutter is open. In order toclose the shutter, the bulb 20 'is again compressed, the thumb or finger then placed upon the orifice 22, and the bulb allowed to expand. This withdraws the air from the cylinder 18, pulls'in the piston 17 turns the cranks 15, 13, 12 and 23', until the spring 24 is again past center, when the spring tension will be added to the suction past center on effect on the piston to accelerate the return 5 cylinder, a rod secured tothe piston-and pro ecti 'ng.from one end of the cylinder, mechanism between said rod and said shutter, whereby when said rod is moved in one direction, the shutter will be opened, anda spring'normally closing said shutter, sald springbeing connected to" an dscillating part of the shutterand having'itsanchorage adjusted with respect thereto so that when the shuttris-bpen the spring will be past the 'center of oscillation in one direction, and when the shutter is closed the spring Wlll.

be past the center ofoscillation in the other direction.

2. The combination with a lens board carrying shutter leaves, of pneumatic cushioning means disconnected from but operating to Prevent noise and absorb jarsand Vibrations incident to the operation of the leaves, and a spring connected at one end to the lens board-and atthe'other end to an oscillating' portion of the leaves, the point of securing to the lens board being so ad usted with respect to theosclllatingpoint. that the s'pringiwill go past center in oppositedirecto. the lens board being soadjusted with rep t to the sci n p intt at e sp will go past center in opposite directions when the shutter is closed and when, it is open.,' e of 4. The combination with a lens board and shutter leaves carried thereby, of pneumatic cushioning means disposed. at an angle to the lens board and disconnected from the leaves, means connecting the leaves for opposite but simultaneous movement, a'crank'on one leaf, and a spring connecting said crank to the lens board ata point soadjusted that the spring will move past the center of oscillation'of the crank in opposite' directions when the shutter is open and when it is closed. 7 r j a f K 5. The combination with a lens board and shutterleaves carried thereby, of pneumatic cushioning means disposed to one isideof and at an angle to the lens board and disconnected from the" leaves, means connecting the; leaves for; opposite but simultaneous movement,- a crank ononeleaf, and a spring connecting said crank'to, the lens'bbardat a point so adjusted that the spring will move past the center of oscillation of theic'rank in opposite directions when the "shutter is open and when it'is closed. I 6. In a mechanism of the character described, the combination with alframe or lens board having an opening therein, and dent to the operation of the shutter, and

a shutter normally closing said opening, of mechanical operating means for the shutter 10 a pneumatic controlling device secured to so operating as to move past center in each the frame, means for operating said pneudirection When the shutter is opened and matic device, a connection from said device closed by the pneumatic controlling device.

to the shutter, pneumatic cushioning means In testimony whereof I affix my signature.

disconnected from but operating to prevent noise and absorb Jars and vibrations inci- J OSEF BRANDSTETTER.

Copies of this patent may be obtained tor five cents each, by addressing the Commissioner of Patentl, Washington, D. 0. 

